July 1, 2006 Subject:
Good review of weight and normal forces.
This lesson starts off with a simple explanation of Newton's 3rd law and then seques into force diagrams and how to apply Newton's 2nd law. I think that the part of this lesson using Newton's 2nd law should be moved to the 2nd law lesson. Then more examples of Newton's 3rd law could be added. For example, a big moving truck is pushed by a small car. How does the force exerted by the truck on the car compare to the force exerted by the car on the truck? According to Newton's 3rd law, they are equal. This is a concept that most people have trouble with. Give more examples so students can really start to "get it".